dev_iommu_ops() is essentially only used in iommu subsystem, so move to a private header to avoid being abused by other drivers.

Suggested-by: Jason Gunthorpe jgg@nvidia.com Reviewed-by: Kevin Tian kevin.tian@intel.com Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com --- drivers/iommu/iommu-priv.h | 11 +++++++++++ include/linux/iommu.h | 11 ----------- 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h index e3e3b2015854..2024a2313348 100644 --- a/drivers/iommu/iommu-priv.h +++ b/drivers/iommu/iommu-priv.h @@ -6,6 +6,17 @@

#include <linux/iommu.h>

+static inline const struct iommu_ops *dev_iommu_ops(struct device *dev) +{ + /* + * Assume that valid ops must be installed if iommu_probe_device() + * has succeeded. The device ops are essentially for internal use + * within the IOMMU subsystem itself, so we should be able to trust + * ourselves not to misuse the helper. + */ + return dev->iommu->iommu_dev->ops; +} + int iommu_group_replace_domain(struct iommu_group *group, struct iommu_domain *new_domain);

diff --git a/include/linux/iommu.h b/include/linux/iommu.h index d31642596675..e0245aa82b75 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -450,17 +450,6 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather) }; }

-static inline const struct iommu_ops *dev_iommu_ops(struct device *dev) -{ - /* - * Assume that valid ops must be installed if iommu_probe_device() - * has succeeded. The device ops are essentially for internal use - * within the IOMMU subsystem itself, so we should be able to trust - * ourselves not to misuse the helper. - */ - return dev->iommu->iommu_dev->ops; -} - extern int bus_iommu_probe(const struct bus_type *bus); extern bool iommu_present(const struct bus_type *bus); extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap);

Under nested IOMMU translation, userspace owns the stage-1 translation table (e.g. the stage-1 page table of Intel VT-d or the context table of ARM SMMUv3, and etc.). Stage-1 translation tables are vendor specific, and need to be compatible with the underlying IOMMU hardware. Hence, userspace should know the IOMMU hardware capability before creating and configuring the stage-1 translation table to kernel.

This adds IOMMU_GET_HW_INFO ioctl to query the IOMMU hardware information (a.k.a capability) for a given device. The returned data is vendor specific, userspace needs to decode it with the structure by the output @out_data_type field.

As only physical devices have IOMMU hardware, so this will return error if the given device is not a physical device.

Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Reviewed-by: Kevin Tian kevin.tian@intel.com Co-developed-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com --- drivers/iommu/iommufd/device.c | 73 +++++++++++++++++++++++++ drivers/iommu/iommufd/iommufd_private.h | 1 + drivers/iommu/iommufd/main.c | 3 + include/uapi/linux/iommufd.h | 39 +++++++++++++ 4 files changed, 116 insertions(+)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 90f88c295ce0..ce78c3671539 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -4,6 +4,7 @@ #include <linux/iommufd.h> #include <linux/slab.h> #include <linux/iommu.h> +#include <uapi/linux/iommufd.h> #include "../iommu-priv.h"

#include "io_pagetable.h" @@ -1119,3 +1120,75 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, return rc; } EXPORT_SYMBOL_NS_GPL(iommufd_access_rw, IOMMUFD); + +int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) +{ + struct iommu_hw_info *cmd = ucmd->cmd; + void __user *user_ptr = u64_to_user_ptr(cmd->data_uptr); + const struct iommu_ops *ops; + struct iommufd_device *idev; + unsigned int data_len; + unsigned int copy_len; + void *data; + int rc; + + if (cmd->flags || cmd->__reserved) + return -EOPNOTSUPP; + + idev = iommufd_get_device(ucmd, cmd->dev_id); + if (IS_ERR(idev)) + return PTR_ERR(idev); + + ops = dev_iommu_ops(idev->dev); + if (ops->hw_info) { + data = ops->hw_info(idev->dev, &data_len, &cmd->out_data_type); + if (IS_ERR(data)) { + rc = PTR_ERR(data); + goto out_put; + } + + /* + * drivers that have hw_info callback should have a unique + * iommu_hw_info_type. + */ + if (WARN_ON_ONCE(cmd->out_data_type == + IOMMU_HW_INFO_TYPE_NONE)) { + rc = -ENODEV; + goto out_free; + } + } else { + cmd->out_data_type = IOMMU_HW_INFO_TYPE_NONE; + data_len = 0; + data = NULL; + } + + copy_len = min(cmd->data_len, data_len); + if (copy_to_user(user_ptr, data, copy_len)) { + rc = -EFAULT; + goto out_free; + } + + /* + * Zero the trailing bytes if the user buffer is bigger than the + * data size kernel actually has. + */ + if (copy_len < cmd->data_len) { + if (clear_user(user_ptr + copy_len, cmd->data_len - copy_len)) { + rc = -EFAULT; + goto out_free; + } + } + + /* + * We return the length the kernel supports so userspace may know what + * the kernel capability is. It could be larger than the input buffer. + */ + cmd->data_len = data_len; + + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); +out_free: + kfree(data); +out_put: + iommufd_put_object(&idev->obj); + return rc; +} diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 5a45b8ba2e26..2c58670011fe 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -296,6 +296,7 @@ iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id) }

void iommufd_device_destroy(struct iommufd_object *obj); +int iommufd_get_hw_info(struct iommufd_ucmd *ucmd);

struct iommufd_access { struct iommufd_object obj; diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 5f7e9fa45502..e71523cbd0de 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -305,6 +305,7 @@ static int iommufd_option(struct iommufd_ucmd *ucmd)

union ucmd_buffer { struct iommu_destroy destroy; + struct iommu_hw_info info; struct iommu_hwpt_alloc hwpt; struct iommu_ioas_alloc alloc; struct iommu_ioas_allow_iovas allow_iovas; @@ -337,6 +338,8 @@ struct iommufd_ioctl_op { } static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = { IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct iommu_destroy, id), + IOCTL_OP(IOMMU_GET_HW_INFO, iommufd_get_hw_info, struct iommu_hw_info, + __reserved), IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc, __reserved), IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl, diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index ac11ace21edb..e01d5ac00dc3 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -46,6 +46,7 @@ enum { IOMMUFD_CMD_OPTION, IOMMUFD_CMD_VFIO_IOAS, IOMMUFD_CMD_HWPT_ALLOC, + IOMMUFD_CMD_GET_HW_INFO, };

/** @@ -379,4 +380,42 @@ struct iommu_hwpt_alloc { enum iommu_hw_info_type { IOMMU_HW_INFO_TYPE_NONE, }; + +/** + * struct iommu_hw_info - ioctl(IOMMU_GET_HW_INFO) + * @size: sizeof(struct iommu_hw_info) + * @flags: Must be 0 + * @dev_id: The device bound to the iommufd + * @data_len: Input the length of a user buffer in bytes. Output the length of + * data that kernel supports + * @data_uptr: User pointer to a user-space buffer used by the kernel to fill + * the iommu type specific hardware information data + * @out_data_type: Output the iommu hardware info type as defined in the enum + * iommu_hw_info_type. + * @__reserved: Must be 0 + * + * Query an iommu type specific hardware information data from an iommu behind + * a given device that has been bound to iommufd. This hardware info data will + * be used to sync capabilities between the virtual iommu and the physical + * iommu, e.g. a nested translation setup needs to check the hardware info, so + * a guest stage-1 page table can be compatible with the physical iommu. + * + * To capture an iommu type specific hardware information data, @data_uptr and + * its length @data_len must be provided. Trailing bytes will be zeroed if the + * user buffer is larger than the data that kernel has. Otherwise, kernel only + * fills the buffer using the given length in @data_len. If the ioctl succeeds, + * @data_len will be updated to the length that kernel actually supports, + * @out_data_type will be filled to decode the data filled in the buffer + * pointed by @data_uptr. Input @data_len == zero is allowed. + */ +struct iommu_hw_info { + __u32 size; + __u32 flags; + __u32 dev_id; + __u32 data_len; + __aligned_u64 data_uptr; + __u32 out_data_type; + __u32 __reserved; +}; +#define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO) #endif

Add intel_iommu_hw_info() to report cap_reg and ecap_reg information.

Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Acked-by: Lu Baolu baolu.lu@linux.intel.com Reviewed-by: Kevin Tian kevin.tian@intel.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com --- drivers/iommu/intel/iommu.c | 19 +++++++++++++++++++ include/uapi/linux/iommufd.h | 23 +++++++++++++++++++++++ 2 files changed, 42 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 5c8c5cdc36cf..9e6f78830ece 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -22,6 +22,7 @@ #include <linux/spinlock.h> #include <linux/syscore_ops.h> #include <linux/tboot.h> +#include <uapi/linux/iommufd.h>

#include "iommu.h" #include "../dma-iommu.h" @@ -4732,8 +4733,26 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid) intel_pasid_tear_down_entry(iommu, dev, pasid, false); }

+static void *intel_iommu_hw_info(struct device *dev, u32 *length, u32 *type) +{ + struct device_domain_info *info = dev_iommu_priv_get(dev); + struct intel_iommu *iommu = info->iommu; + struct iommu_hw_info_vtd *vtd; + + vtd = kzalloc(sizeof(*vtd), GFP_KERNEL); + if (!vtd) + return ERR_PTR(-ENOMEM); + + vtd->cap_reg = iommu->cap; + vtd->ecap_reg = iommu->ecap; + *length = sizeof(*vtd); + *type = IOMMU_HW_INFO_TYPE_INTEL_VTD; + return vtd; +} + const struct iommu_ops intel_iommu_ops = { .capable = intel_iommu_capable, + .hw_info = intel_iommu_hw_info, .domain_alloc = intel_iommu_domain_alloc, .probe_device = intel_iommu_probe_device, .probe_finalize = intel_iommu_probe_finalize, diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index e01d5ac00dc3..b4ba0c0cbab6 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -372,13 +372,36 @@ struct iommu_hwpt_alloc { }; #define IOMMU_HWPT_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_ALLOC)

+/** + * struct iommu_hw_info_vtd - Intel VT-d hardware information + * + * @flags: Must be 0 + * @__reserved: Must be 0 + * + * @cap_reg: Value of Intel VT-d capability register defined in VT-d spec + * section 11.4.2 Capability Register. + * @ecap_reg: Value of Intel VT-d capability register defined in VT-d spec + * section 11.4.3 Extended Capability Register. + * + * User needs to understand the Intel VT-d specification to decode the + * register value. + */ +struct iommu_hw_info_vtd { + __u32 flags; + __u32 __reserved; + __aligned_u64 cap_reg; + __aligned_u64 ecap_reg; +}; + /** * enum iommu_hw_info_type - IOMMU Hardware Info Types * @IOMMU_HW_INFO_TYPE_NONE: Used by the drivers that do not report hardware * info + * @IOMMU_HW_INFO_TYPE_INTEL_VTD: Intel VT-d iommu info type */ enum iommu_hw_info_type { IOMMU_HW_INFO_TYPE_NONE, + IOMMU_HW_INFO_TYPE_INTEL_VTD, };

/**